Oxidized LDL induces in vitro lymphocyte activation in antiphospholipid syndrome

Non-invasive imaging in antiphospholipid syndrome to assess subclinical coronary artery disease

Antiphospholipid antibody syndrome (usually named antiphospholipid syndrome, APS) is an autoimmune disorder seen mainly in young people. Clinically, APS is described by pregnancy complications and/or a hypercoagulable state, including the venous or arterial vasculature, and strongly related to antiphospholipid antibodies. Although several cardiac manifestations have been involved with APS, and accelerated atherosclerosis is present in this condition, little is known about cardiovascular (CV) risk and the relation between APS. Several studies have used imaging markers to associate them with the main clinical features of patients with APS and the probability of having subclinical atherosclerosis. However, it has not yet been established which markers are most related to the risk of developing CV diseases (CVD) in these patients. In this narrative review, we focus on non-invasive imaging markers that can predict CVD, including carotid intima-media thickness and carotid plaques assessed by carotid ultrasonography or coronary artery calcium score, which usually by computed tomography. We also examine the evidence about vascular function markers used in APS, such as arterial flow-mediated brachial dilation and artery stiffness measured by the velocity of the pulse wave. We present the current status of non-invasive imaging markers, which suggest the existence of subclinical atherosclerosis in patients with APS. However, new prospective research is required to identify the predictive value of these findings and their modification by current treatments for APS.

ApoA-I mimetics reduce systemic and gut inflammation in chronic treated HIV

Novel therapeutic strategies are needed to attenuate increased systemic and gut inflammation that contribute to morbidity and mortality in chronic HIV infection despite potent antiretroviral therapy (ART). The goal of this study is to use preclinical models of chronic treated HIV to determine whether the antioxidant and anti-inflammatory apoA-I mimetic peptides 6F and 4F attenuate systemic and gut inflammation in chronic HIV. We used two humanized murine models of HIV infection and gut explants from 10 uninfected and 10 HIV infected persons on potent ART, to determine the in vivo and ex vivo impact of apoA-I mimetics on systemic and intestinal inflammation in HIV. When compared to HIV infected humanized mice treated with ART alone, mice on oral apoA-I mimetic peptide 6F with ART had consistently reduced plasma and gut tissue cytokines (TNF-α, IL-6) and chemokines (CX3CL1) that are products of ADAM17 sheddase activity. Oral 6F attenuated gut protein levels of ADAM17 that were increased in HIV-1 infected mice on potent ART compared to uninfected mice. Adding oxidized lipoproteins and endotoxin (LPS) ex vivo to gut explants from HIV infected persons increased levels of ADAM17 in myeloid and intestinal cells, which increased TNF-α and CX3CL1. Both 4F and 6F attenuated these changes. Our preclinical data suggest that apoA-I mimetic peptides provide a novel therapeutic strategy that can target increased protein levels of ADAM17 and its sheddase activity that contribute to intestinal and systemic inflammation in treated HIV. The large repertoire of inflammatory mediators involved in ADAM17 sheddase activity places it as a pivotal orchestrator of several inflammatory pathways associated with morbidity in chronic treated HIV that make it an attractive therapeutic target.

Interleukin-17/Interleukin-21 and Interferon-γ producing T cells specific for β2 Glycoprotein I in atherosclerosis inflammation of systemic lupus erythematosus patients with antiphospholipid syndrome

Systemic lupus erythematosus is frequently associated with antiphospholipid syndrome. Patients with lupus-antiphospholipid syndrome are characterized by recurrent arterial/venous thrombosis, miscarriages, and persistent presence of autoantibodies against phospholipid-binding proteins, such as β2-Glycoprotein I. We investigated the cytokine production induced by β2-Glycoprotein I in activated T cells that infiltrate in vivo atherosclerotic lesions of lupus-antiphospholipid syndrome patients. We examined the helper function of β2-Glycoprotein I-specific T cells for tissue factor production, as well as their cytolytic potential and their helper function for antibody production. Lupus-antiphospholipid syndrome patients harbor in vivo activated CD4⁺ T cells that recognize β2-Glycoprotein I in atherosclerotic lesions. β2-Glycoprotein I induces T-cell proliferation and expression of both Interleukin-17/Interleukin-21 and Interferon-γ in plaque-derived T-cell clones. β2-Glycoprotein I-specific T cells display strong help for monocyte tissue factor production, and promote antibody production in autologous B cells. Moreover, plaque-derived β2-Glycoprotein I-specific CD4⁺ T lymphocytes express both perforin-mediated and Fas/FasLigand-mediated-cytotoxicity. Altogether, our results indicate that β2-Glycoprotein I is able to elicit a local Interleukin-17/Interleukin-21 and Interferon-γ inflammation in lupus-antiphospholipid syndrome patients that might lead, if unabated, to plaque instability and subsequent arterial thrombosis, suggesting that the T helper 17/T helper 1 pathway may represent a novel target for the prevention and treatment of the disease.

β2 Glycoprotein I Recognition Drives Th1 Inflammation in Atherosclerotic Plaques of Patients with Primary Antiphospholipid Syndrome

Antiphospholipid syndrome (APS) is characterized by recurrent arterial/venous thrombosis and miscarriages in the persistent presence of autoantibodies against phospholipid-binding proteins (aPLs), such as β2 glycoprotein I (β2GPI). In addition to the aPL thrombophilic effect, arterial thrombosis was related to accelerated atherosclerosis in animal models; however, contrasting findings were reported in primary APS patients with regard to the increased number of plaques or abnormal arterial wall thickness. We investigated the cytokine production induced by β2GPI in activated T cells that infiltrate in vivo atherosclerotic lesions of primary APS patients with atherothrombosis. We also examined the helper function of β2GPI-specific T cells for monocyte matrix metalloproteinase-9 and tissue factor production, as well as their cytolytic potential and their helper function for Ab production. APS patients with atherothrombosis harbor in vivo-activated CD4⁺ T cells that recognize β2GPI in atherothrombotic lesions. β2GPI induces T cell proliferation and IFN-γ expression in plaque-derived T cell clones. β2GPI-specific T cells display helper function for monocyte matrix metalloproteinase-9 and tissue factor production and promote Ig production in autologous B cells. Moreover, plaque-derived β2GPI-specific CD4⁺ T lymphocytes express perforin-mediated and Fas/Fas ligand-mediated cytotoxicity. β2GPI, and especially the DI domain, drive a local Th1 inflammatory response, with subsequent plaque instability that eventually favors atherothrombosis. This finding may explain the association between aPLs and arterial thrombosis, despite the lack of evidence of surrogate markers for atherosclerosis in primary APS.

Oxidized lipoproteins are associated with markers of inflammation and immune activation in HIV-1 infection

OBJECTIVE

The pathogenesis of immune dysfunction in chronic HIV-1 infection is unclear, and a potential role for oxidized lipids has been suggested. We hypothesize that both oxidized HDL and LDL (HDLox and LDLox) contribute to HIV-1-related immune dysfunction.

STUDY

In the AIDS Clinical Trials Group A5260, 234 HIV-infected antiretroviral therapy (ART)-naive participants were randomized to receive tenofovir-emtricitabine and protease inhibitors or raltegravir and had HIV-1 RNA less than 50 copies/ml by week 24 and thereafter.

METHODS

Associations between biomarkers of inflammation (IL-6, high-sensitivity C-reactive protein and D-dimer), immune activation (sCD163, sCD14, soluble IL-2 receptor, CD38 and HLA-DR), inflammatory monocytes (CD14CD16), T-cell senescence (CD28 and CD57) and exhaustion (PD1), and HDLox, LDLox were assessed at entry and after ART (week 96) with Spearman (partial) correlations.

RESULTS

HDLox declined and LDLox increased over 96 weeks of ART. Positive associations were observed at baseline and over time between HDLox (but not consistently for LDLox) and most markers of inflammation and immune activation (but not senescence/exhaustion), even after adjustment for multiple comparisons, demographics, entry CD4 cell count and HIV-1 RNA. HDLox was positively associated with IL-6 (r = 0.19 - 0.29, P < 0.01) and sCD163 (r = 0.14 - 0.41, P ≤ 0.04) at all time points.

CONCLUSION

These prospective longitudinal data suggest that oxidized lipoproteins may contribute to persistent immune activation on ART.

Cardiovascular risk factors in the antiphospholipid syndrome

A major cause of morbidity and mortality in the context of the antiphospholipid syndrome (APS) is the occurrence of thrombotic events. Besides the pathogenic roles of antiphospholipid antibodies (aPL), other risk factors and medical conditions, which are conditions for traditional risk of an individual without the APS, can coexist in this patient, raising their risk of developing thrombosis. Therefore, the clinical and laboratory investigation of comorbidities known to increase cardiovascular risk in patients with antiphospholipid antibody syndrome is crucial for the adoption of a more complete and effective treatment. Experimental models and clinical studies show evidence of association between APS and premature formation of atherosclerotic plaques. Atherosclerosis has major traditional risk factors: hypertension, diabetes mellitus, obesity, dyslipidemia, smoking, and sedentary lifestyle that may be implicated in vascular involvement in patients with APS. The influence of nontraditional risk factors as hyperhomocysteinemia, increased lipoprotein a, and anti-oxLDL in the development of thromboembolic events in APS patients has been studied in scientific literature. Metabolic syndrome with all its components also has been recently studied in antiphospholipid syndrome and is associated with arterial events.

Oxidized LDL and LOX-1 in experimental sepsis

Oxidized low-density lipoproteins (oxLDL) and the lectin-like oxLDL receptor-1 (LOX-1) are upregulated in inflammation. Because of the importance of inflammation and capillary leakage in the impairment of the microcirculation, which in turn contributes to the development of sepsis and multiorgan failure, the role of oxidized LDL and LOX-1 as players of intestinal inflammation is of great interest. In fact, the blockade of LOX-1 during experimental endotoxemia was effective in reducing leukocyte activation. There are several mechanisms by which oxLDL can participate in local and systemic inflammation, including cell proliferation, apoptosis, capillary perfusion, leukocyte-endothelial cell interactions, and endothelial activation. This review highlights the evidence relating oxLDL and LOX-1 to proinflammatory disease mechanisms. We also indicate situations when oxLDL, because of exposure time, dose, or degree of oxidization, is involved in disease resolution. Modulation of LOX-1 response could be utilized for the treatment of local and systemic inflammation, but the successful use of this target requires further understanding of its broad effects.

Comparative assessment of vascular function in autoimmune rheumatic diseases: considerations of prevention and treatment

Numerous autoimmune-inflammatory rheumatic diseases have been associated with accelerated atherosclerosis or other types of vasculopathy leading to increased cardio- and cerebrovascular disease risk. Traditional risk factors, as well as the role of systemic inflammation including cytokines, chemokines, proteases, autoantibodies, adhesion receptors and others have been implicated in the development of these vascular pathologies. The characteristics of vasculopathies may significantly differ depending on the underlying disease. While classical accelerated atherosclerosis has been associated with rheumatoid arthritis (RA), systemic lupus erythematosus (SLE) or spondyloarthropathies (SpA), obliterative vasculopathy may rather be characteristic for systemic sclerosis (SSc) or mixed connective tissue disease (MCTD). Antiphospholipid antibodies have been implicated in vasculopathies underlying SLE, antiphospholipid syndrome (APS), RA and MCTD. There is also heterogeneity with respect to inflammatory risk factors. Cytokines, such as tumor necrosis factor-α (TNF-α) or interleukin 6 (IL-6) and immune complexes are primarily involved in arthritides, such as RA, SpA, as well as in SLE. On the other hand, autoantibodies including anti-oxLDL anti-cardiolipin and anti-β2GPI are rather involved in SLE- and APS-associated vasculopathies. Regarding the non-invasive assessment of vascular function, endothelial dysfunction, overt atherosclerosis and vascular stiffness may be indicated by brachial artery flow-mediated vasodilation (FMD), common carotid intima-media thickness (ccIMT) and aortic pulse-wave velocity (PWV), respectively. These abnormalities have been described in most inflammatory rheumatic diseases. While ccIMT and stiffness are relatively stable, FMD may be influenced by many confounding factors. In addition to traditional vasculoprotection, immunosuppressive agents including corticosteroids, traditional and biologic DMARDs may have significant vascular and metabolic effects. The official EULAR recommendations on the assessment and management of cardiovascular disease in arthritides have just been published, and similar recommendations in connective tissue diseases are to be developed soon.